1. Field of the Invention
The present invention relates to a belt tension adjustment apparatus and a robot arm having the same, and more particularly, to a belt tension adjustment apparatus and a robot arm having the same capable of precisely adjusting a moving position of the robot arm to convey a wafer to a normal position.
2. Description of the Related Art
In order to manufacture a semiconductor device, various chemical and physical processes are performed using various processing apparatuses. In addition, a wafer-conveyance process is required in order to perform a unit process in the processing apparatus.
A conveyance apparatus used in the wafer-conveyance process includes various motors, gears, belts, and so on. Typically, a belt may be driven by a motor to drive an arm on a wafer loader and a reticle loader to smoothly use power and perform precise operation. While it may depend on materials and the purposes of use, the belt may deteriorate and loosen over time, resulting in reduced elasticity.
Generally, a power transmission belt is wound on a drive pulley and a driven pulley of a driven shaft. A belt connector securely connects the power transmission belt, and the power transmission belt has an arm drive part for driving an arm.
The power transmission belt is driven by rotation of the drive pulley. In order to receive uniform rotational power from the drive pulley without any loss, the belt should maintain a uniform tension between the drive pulley and the driven pulley. When the power transmission belt maintains uniform tension, the arm drive part can straightly move with uniform speed and acceleration.
However, when the power transmission belt is used for a long time, the power transmission belt deteriorates and loosens, thereby generating sagging. As a result, the power transmission belt moves in a serpentine manner between the drive and driven pulleys,
Therefore, it is difficult to smoothly transmit rotational power from the drive pulley to the arm drive part. As a result, the arm drive part, which is used as a wafer loader or a reticle loader, cannot be precisely positioned, and thus generates many errors. It is even worse when the power transmission belt may be separated from the belt pulleys to stop the operation. While an operator may appropriately stop the operation and replace the belt, it is difficult to estimate an exchange cycle of the belt, since the exchange cycle of the belt may vary depending on equipment and use environment of the drive part. Additionally, loss may be generated due to incorrect exchange.